The New Zealand Qualifications Authority has urged parents to treat comparisons of school's NCEA results with caution.
The authority has published last year's National Certificate of Educational Achievement results on its website.
The figures show more than 100,000 students achieved one of the three levels of the NCEA last year.
They also show achievement gaps between Maori and non-Maori, Pasifika and non-Pasifika, and girls and boys continued.
But Radio New Zealand's education correspondent says one of the largest gaps was between rich and poor schools.
NCEA achievement rates at each year level were as much as 24 percentage points lower in low-decile schools than in the highest decile schools.
That achievement gap narrowed at NCEA levels one and two if students stayed on at school.
NZQA chief executive Bali Haque says factors like decile, student numbers and the courses offered will effect each school's results.
